The present invention relates in general to fluid flow control devices, and in particular to a dual basket or duplex strainer for trapping solid particles entrained in fluid flowing through the strainer.
U.S. Pat. Nos. 3,679,060; 3,757,956 and 3,768,654 disclose prior art dual basket strainers, each having a single, user actuated, control mechanism for directing fluid flow through one or the other of a pair of removable strainer baskets contained in respective chambers of the strainer housing. Such a feature allows a clogged strainer basket to be removed for cleaning as fluid flow through the strainer continues via the other strainer basket.
The noted prior art strainer control mechanisms each include an inlet valve mechanism in fluid communication between a strainer inlet and the strainer basket containing chambers, and an outlet valve mechanism in fluid communication between the chambers and a strainer outlet. Both valve mechanisms are user actuated by a common control shaft wherein fluid communication between the inlet, the outlet, and a selected one of the strainer chambers is dependent upon the position of the control shaft.
It can be appreciated that such prior art strainer control mechanisms are relatively complex and therefore expensive to manufacture, and may, because of their complexity, be prone to seal leakage. Further, the force required to simultaneously operate bolh valve mechanisms by means of a single control shaft may be relatively high so as to make difficult the operation of the strainer. Also, relatively complex, user actuated, dual valve strainer control mechanisms can be difficult to maintain.
Accordingly, it is a primary aim of the present invention to provide a dual basket strainer which overcomes each of the aforementioned shortcomings without offsetting disadvantages.